Maize streak disease (MSD) is one of the most destructive diseases of maize (Zea mays L.) estimated to cause a yield loss of about 20% in Ghana. Field experiment was conducted at Nkwanta in the Volta Region of Ghana during the cropping seasons of 2015 to assess the effects of tillage practices, fertilizer application and maize variety on the incidence and severity of MSD. The MSD severity was assessed using 1 to 5 visual scale (1=no symptom and 5= very severe symptom). The relationship between total N, available P and exchangeable K contents of soils and maize leaves sampled at silking stage and MSD incidence and severity were elucidated with Pearson correlation coefficients. Although symptoms were observed in both fertilized and non-fertilized plants, fertilizer addition effectively reduced the MSD impact on growth and yield. Incidence and severity of MSD under no-tillage system were significantly lower than under conventional tillage. Severe MSD, particularly, of plants on the plots with no added nutrients led to stunted growth and reduced grain yield. The severity of MSD correlated positively with maize leaf N content, while increasing leaf K content resulted in reduced MSD severity. It can therefore be concluded that tillage and plant nutrition affect the severity of MSD in tropical soil.

Maize streak disease (MSD) is the most devastating and destructive disease of maize (Zea maysL.) in sub-Saharan Africa (SSA). Field trials were conducted in the 2014 minor and 2015 major cropping seasons to screen 16 and 17 maize genotypes, respectively, for high yield and resistance to maize streak virus (MSV) infections. The plants were scored for disease severity at 4, 6, 8 and 10 weeks after planting (WAP) based on a 1-5 visual scale (1=No infection and 5=Very severe infection). Polymerase chain reaction (PCR) test was done to detect the presence of MSV in the diseased leaf samples in order to confirm field resistance. Both phenotypic and PCR test revealed that all the maize genotypes tested in the study were infected by MSV. There was a significant varietal effect on the incidence and severity of MSD in both the major and minor seasonal trials. Genotypes ‘Abontem’,’Aburohemaa’, ‘Akposoe’, ‘Dapango’, ‘Dorke’, ‘Etubi’, ‘Honampa’, ‘Mamaba’, ‘Obatanpa’, ‘Omankwa’ and PAN 12 showed mild disease symptoms during both major and minor cropping seasons. On the other hand, genotypes ‘Dormabin’, ‘Dzinu-Eve’, ‘Enibi’, Keta 60 and PAN 53 exhibited moderate to severe symptoms during the two cropping seasons. Incidence and severity of MSD were significantly higher in the minor season than in the major season, indicating a significant seasonal effect of MSV on the maize genotypes. The yield and yield components were observed to vary significantly among the different maize genotypes and between the cropping seasons with mean yields significantly higher in the major season than in the minor season. Genotypes ‘Abontem’, ‘Aburohemaa’, ‘Akposoe’, ‘Dorke’, ‘Etubi’, ‘Honampa’, ‘Omankwa’, ‘Obatanpa’ and PAN 12 (All improved varieties), which exhibited partial resistance to MSV infection gave high seed yields during both seasons. The improved maize genotypes that were high yielding and resistant to MSV infection should be evaluated for uniform yield trials on farmers’ fields towards their release as varieties to farmers.